A test system having a sub-system to sub-system bridge is a system for troubleshooting circuits. When troubleshooting circuits in a telecommunications network, for example, testing circuit functionality may occur using a passive circuit test, or by injecting a test signal into the circuit (active testing), or any other form of circuit testing. However, these forms of circuit testing each have deficiencies in troubleshooting and diagnosing circuits in a network. For example, when passively testing a circuit, circuit telemetry, e.g. circuit fault and alarm data sent by the circuit, test signals are input into the circuit to determine circuit responsiveness. Also, a passive circuit test fails to sectionalize a circuit under test causing difficulty in pinpointing circuit problems. Actively testing a circuit may fail to touch a designated element with the circuit because such testing cannot loop all requested test points within the circuit. Also, active testing cannot be used on all circuit elements and may not have a point of reference for testing a circuit, because a technician may not have an indication of where the circuit is operating incorrectly.